Sanding head



Oct. 7, 1958 o. so; HAVEN 2,854,798

sANnING HEAD Filed Oct. 50, 1957 2 Sheets-Sheet 1 man-7,1958 o. s. DEHAvEN 2,854,798

SANDING HEAD Filed Oct. 30, 1957 2 Sheets-Sheet 2 #frag/vf rg -eratingand at-rest conditions.

United States Patent C) SANDING HEAD Oliver S. De Haven, Indianapolis,Ind. Application October 36, 1957, Serial No. 693,365 Claims. (Cl.51193.7)

This invention relates to a rotatable sanding head of the type employinga plurality of radially projecting strips of abrasive engageable with awork-piece and supported during rotation of the head by a plurality ofradially projecting brushes.

Heretofore the abrasive strips in such sanding heads were either woundon a common spool or in separate coils lixedly retained in the sandinghead. In either event, it was a cumbersome time-consuming task toreplace the abrasive strips, and it required a complete stoppage of theequipment to manually feed fresh abrasive material from the spool orcoils. In the common spool arrangement, only a relatively short supplyof strips could be used, and the percentage of Waste was high. With theseparate coil arrangement, non-uniform lengths of the abrasive stripswere fed out which produced a poor quality sanding operation and alsoproduced excessive waste.

It is the general object of my invention to provide a sanding head whichwill overcome the difficulties and disadvantages of the previous heads.More specifically, it is an object of my invention to provide arotatable sanding head which is adapted to carry a plurality of spoolsof abrasive strips, which will permit the convenient and rapidreplacement `of said spools, and which can be varied in width to takedifferent widths of abrasive strips. It is another object of myinvention to provide a rotatable sanding head which Will dispenseabrasive strips simultaneously from all the spools of the head and willdispense uniform predetermined lengths of abrasive material from theindividual spools, and which Will dispense said abrasive strips bothwhile the head is rotating and while it is at rest.

ln accordance with my invention, the sanding head comprises a Vpair ofend members or assemblies, conveniently in the form of spiders, adaptedto be mounted in spaced relation on a rotating shaft. The end membersare adapted to carry a series of brushes projecting from spaced pointsabout the periphery of the head, and are further adapted to carry spoolsof abrasive strips inwardly of such brushes to feed abrasive strips tothe leading faces of the brushes. The spools are removably mounted onspindles which are geared together, as by planetary gear means, orotherwise interconnected for simultaneous feeding movements, and meansis provided to actuate the spools to feed abrasive strips therefrom.Preferably, the gear train between the spools is driven by relativerotation between the head and a drum carried with the head, as by meansof a worm gear mechanism which advances the spool gears through apredetermined feeding movement for each actuation of the drum relativeto the head. The drum may be rotated relative to the head either byretarding drum rotation when the head is rotating or by,manually'rotating the drum when the head is at rest, so

that the feeding operation may be effected under both op- The spool geartrain and Vof the spider 11, in a paired arrangement.

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the operating mechanism therefor are desirably carried with one of theend members or assemblies of the head, as a self-contained assembly, andthe opposite end member or assembly is adapted to be mounted atdifferent axial distances therefrom with the brushes and abrasive spoolsbeing supported between the two end members. Conveniently, the axialdistance between the two end members can be varied to receive brushesand spools of different widths and thus to form heads of different axialwidths.

Further objects and features of the invention will bccome apparent fromthe following description, and the accompanying drawings of a specificembodiment of the invention. In the drawings:

Fig. l is a central vertical section through a sanding head embodying myinvention and taken on the line 1 1 of Fig. 2 to show portions thereofin elevation;

Fig. 2 is a vertical section taken on the line 2 2 of Fig. 1

Fig. 3 is a vertical section taken on the line 3-3 of Fig. l;

Fig. of Fig.

Fig. and

Fig.

arms.

The sanding head shown in the drawings comprises a pair of end members,or spiders 10 and 11, each having a plurality of radially extending arms12 and 13, and a central mounting hole 14. The spider 10, shown in thedrawings as the outer member of the head, is provided with an outwardlydirected hub 16 in which the hole 14 is formed and by which the spider16 mounted on a rotatable driving shaft 15. The inner spider 11 has acentral hub 17 provided with the hole 14 and is carried on a sleeve 18mounted on the shaft 15 and provided with an annular end flange 19. Thespider 11 is axially positioned on the sleeve 18 by a shoulder 20against which the inner face of the spider 11 abuts.

The spider 10 is spaced axially along the shaft from the sleeve 18 andhence from ,the spider 11 by a spacer sleeve 2l of a length to give thedesired spacing between the two spiders. By using different lengths ofspacers 21 the spiders 10 and 11 can be disposed at different axialdistances from each other to vary the axial length of the head.

The head is retained on the shaft 15 by a nut 24 threaded on the outerend of the shaft and adapted to be tightened against the hub 16 of thespider 10 to clamp the parts together on the driving shaft, betweenitself and a shoulder 25 formed on the driving shaft 15.

Each arm 12 of the spider 10 lies opposite an arm 13 A rigid arms 12 4is a vertical section taken on the line 4-4 1; 5 is a isometric view ofone of the brush holders;

6 is a fragmental side view lof one of the spider channel member 28extends axially between the 'and 13 of each pair and is supportedthereby. Desirably,

each member 28 is a double channel formed with its legs 29 convergingfrom the edges of a pair of webs 30 disposed in back-to-backrelationship. While single channels might be used in heads of shortaxial length the preferred double channels reduce the tendency of thechannels to warp under the centrifugal force generated during operationof the head, especially when the head width has been increased by theuse of a relatively long spacer 21.

The channels 28 are mountedon the spiders 10 and 11 by means of endplates 31 having tapped holes 32 ,for the reception of screws 33extending through the spider arms 12 and 13. Conveniently, the arms areprovided with a plurality of holes 34 through which the screws mayextend, so that by placing the screws 33 in the desired holes 34 to thechannels 28 may be mounted on the spider arms at the desired angle.Desirably, one of the end plates 31 extends over only the inner pair ofchannel legs29 leaving one end of the outer channel open for thereception of a brush.

A brush 3,5 formed from any suitable material, such as horse-hair,nylon, or the like, is releasably retained between each of the pairs ofoutwardly presented channel legs 29 with its bristles projectingoutwardly beyond the ends of the arms for engagement with a workpiece. Abrush 35 is received in each of the channel members 28 by slidablyinserting it between the outer pair of channel legs 29 at the open endof the channel. While each pair of arms 12 and 13 normally carries abrush 35, it is contemplated that lin some sanding operations arelatively small number of 'brushes will be employed; in which case notall of the pairs of arms will carry brushes 35. And in still otherapplications, cloth mats may be substituted for the brushes 35.

Adjacent thebase of Veach of the arms 12 of the spider is aboss 36integrally formed on the outer face thereof `and provided with an endplate 37 threaded thereon. Axially movable in each boss 36 is a spindle40 extending through an opening in the end plate 37 and having a knurledhandle 42 at its outer end normally abutting the end plate. The oppositevend of the spindle 40 extends 'inward through an opening formed'in thespider 10 and is adapted to engage one end of a spool 46 of an abrasivestrip 48. The spindle 40 is biased inwardly by a spring 50 disposedaround the spindle between the inner face of `the end plate 37 and ashoulder 51 formed on the spinldle 40.

A corresponding set of spindles 52 are rotatably mounted on the innerface of the spider 11 and cooperate with the spindles 40 for holdingopposite ends of the spools 46. The abrasive strips 48 extend outwardfrom their respective spools 46 along the leading faces of the brushes35 for engagement with a work-piece upon rotation of the heads. A guidebar 54 secured to the leading lface of each of the channel members 28,as by screws 56, positions and retains the strips 48 in close proximityto the leading face of the brush 35 so that during rotation of the headthe brushes provide exible support for the ends of the abrasive strips48 as they are rotated against a workpiece. In most sanding operations,good results are achieved by having the ends of the strips .48 and thelbrushes 35 projectv substantially the same distances beyond the ends ofthe arms 12 and 13.

In the course of operating the sanding head, Vthe ends of the abrasivestrips 48 become worn and breakroi, and it 'is necessary to replace theworn and broken ends with ,fresh lengths of the abrasive strips. Inorder to feed out fresh lengths of the `strips while the head isrotating, means is provided to drive the spools in a strip feedingdirection during such rotation. To this end, a pinion gear 60 is xedlyretained on each of the spindles 52 as by a key 62. Conveniently, thekeys 62 are of sufficient length to engage the spools 46 to drive themwith the spindles 52. The pinion gears 60 mesh with and are driven by asun gear 64 rotatably mounted on the sleeve 18 and integrally connectedby means of an annular web 66 to a worm gear 68 similarly rotatable onsaid sleeve. Conveniently, the worm and sun gears are axially positionedon the sleeve between the outer end of the spider hub 17 and a snap ring69,at the inner end of the spacer 21.

The worm gear 68 is in mesh with a worm 70 disposed 'chordally ofthespider 11 in a bracket 72 secured to the outer face of the spider 11by bolts 73. The worm 70 is driven by a ratchet from a lever arm 74pivoted on the =axis of the worm 70 and extending through an opening:formed in the web of the spider 11. The free end of the lever arm '74carries a cam follower ball 76 which is received between arpair ofvparallel cam ribs Z8 on the face of a brake drum 80. The brake drum isrotatably received A on the sleeve 18 between the spider 11 and thesleeve flange 19 and is adapted for rotational and counter-rotationalmovement with respect to the spiders 10 and 11.

Desirably, rotational movement of the drum with respect to the spider islimited by a stop lug 82 mounted on the drum 80 and received in anarcuate slot S4 cut in the web of the spider 11. The drum is biasedforward in the direction of rotation of the head by a tension spring S8stretched between a iixed point on the spider 11 and a bracket 86 on theleg 82 of the drum.

Operation of the sanding head may be described as follows:

The sanding head is positioned on the driving shaft 15 in the mannerpreviously described with the brushes 3S projecting from the arms 12 and13 and the spools of abrasive secured on the spindles 46 and S2. Thestrips of abrasive are fed outwardly from the spools between the guidebars 54 and the brushes 35 along the leading faces of the brushes sothat the brushes and strips project substantially the same distance fromthe ends of the arms 12 and 13. Thus, the abrasive strips 48 aresupported by the brushes 35 beyond the ends of the arms 12 and 13 sothat the strips are kept in contact with a work-piece as the head isrotated in the direction of the arrow A of Fig. 2.

After the head has been in operation for a period of time the ends ofthe abrasive strips 48 become worn and break ott and fresh lengths ofthe abrasive material must be unwound from the spools 46. T o feed outfresh abrasive while the head is rotating, a braking force is applied tothe drum to retard its rotation with the sanding head and to cause arelative movement between the drum 80 and the spiders 10 and 11. Theamount of braking force required is extremely small and can be easilyapplied by the operator striking the rim of the drum with the heel ofhis hand. When this braking force is applied to the drum, the drum isthus rotated rearwardly with respect to the forwardly rotating head, theamount of this counter-rotation being limited by the movement of the lug82 in the slot 84. This relative movement between the drum and thesanding head causes the cam ribs 78 to move the cam follower ball 76along their length thereby pivoting the lever arm 74 to rotate the worm70 through a predetermined angle. Rotation of the worm 70 drives theworm gear and sun gear 68 `and 64 on the sleeve 18 in the direction ofthe arrow B in Fig. 2, and rotates the pinion gears 60 to drive thespindles 52 to feed out predetermined lengths of the abrasive strips 48.When the braking force 1s released from the Vdrum 80, the spring 88returns the drum to its starting position and positions the lug 82 at`the left of the Vslot v84, as shown in Fig. 3. Movement of the drum Atoits starting position carries the cam follower 'ball 76 outwardlybetween the cam ribs 78 and the drum 80 is then ready for a new brakeactuation.

While I have described Athe operation of feeding out fresh lengths ofthe abrasive strips when the head is rotating, it is rof course possibleto feed out the strips when vthe head is stationary. Such an operationis accomplished by' manually rotating the drum 80 with respect to thespiders to drive the several gears in the manner previously described.

I claim as my invention:

l. A sanding head, comprising a pair of axially spaced end membersmountable on a rotatable shaft, means ad jacent the periphery of saidend members adapted to releasably lock a plurality of outwardlyprojecting brushes on said end members, a plurality of pairs of spindlescarried on said end members for holding a plurality of spools ofabrasive strips, a planetary gear train operatively interconnecting saidpairs of vspindles for rotating said spindles with respect to the headto unwind the spools, and means movable with respect to the head fordriving said planetary gear train to rotate said spindles when the headis rotating or at rest.

2. Asanding head, comprising a pair of axially spaced end membersmountable on a rotatable shaft, means adjacent the periphery of said endmembers adapted to releasably lock a plurality of outwardly projectingbrushes on said end members, a plurality of pairs of spindles carried onsaid end members for holding a plurality of spools of abrasive strips,one of said spindles in each pair being movable axially of said endmembers for releasably retaining the spools of abrasive in the head, aplanetary gear train operatively interconnecting said pairs of spindlesfor rotating said spindles with respect to the head to unwind thespools, and means movable with respect to the head for driving saidplanetary gear train to rotate said spindles when the head is rotatingor at rest.

3. A sanding head, comprising a pair of axially spaced end membersmountable on a rotatable shaft, means adjacent the periphery of said endmembers adapted to releasably lock a plurality of outwardly projectingbrushes on said end members, a plurality of pairs of spindles carried onsaid end members for holding a plurality of spools of abrasive strips, aplanetary gear train operatively interconnecting said pairs of spindlesfor rotating said spindles with respect to the head to unwind thespools, a drum movable relative to the sanding head and operativelyconnected to said planetary gear train for driving said gear train torotate said spindles when the head is rotating or at rest, and meanslimiting said relative drum movement for limiting the spool unwinding.

4. A sanding head, comprising a pair of axially spaced concentricspiders having a plurality of radially projecting arms, locking meansadjacent the outer ends of said arms adapted for the reception of aplurality of outwardly projecting brushes, a plurality of pairs ofspindles on said spiders adjacent the base of said arms for holding aplurality of spools of abrasive strips, a planetary gear trainoperatively interconnecting said pairs of spindles for rotating saidspindles with respect to the head to unwind the spools, and meansmovable with respect to the head for driving said planetary gear trainto rotate said spindles when the head is rotating or at rest.

5. A sanding head, comprising a pair of axially spaced concentricspiders having a plurality of radially projecting arms, locking meansadjacent the outer ends of said arms adapted for the reception of aplurality of outwardly projecting brushes, a plurality of pairs ofspindles on said spiders adjacent the base of said arms for holding aplurality of spools of abrasive strips, a guide bar adjacent the end ofeach of said arms for disposing the abrasive strips adjacent thebrushes, a planetary gear train operatively interconnecting said pairsof spindles for rotating said spindles with respect to the head tounwind the spools,` and means movable with respect to the head fordriving said planetary gear train to rotate said spindles when the headis rotating or at rest.

6. A sanding head, comprising a pair of axially spaced concentricspiders having a plurality of radially projecting arms, a plurality ofaxially extending channels interconnecting the spiders adjacent theouter ends of said arms and adapted for the reception of a plurality ofoutwardly projecting brushes, a plurality of pairs of spindles on saidspiders adjacent the base of said arms for holding a plurality of spoolsof abrasive strips, a planetary gear train operatively interconnectingsaid pairs of spindles for rotating said spindles with respect to thehead to unwind the spools, and means movable with respect to the headfor driving said planetary gear train to rotate said spindles when thehead is rotating or at rest.

7. A sanding head as set forth in claim 6 in which said channels arepivotally adjustable on said arms for adjusting the angle of projectionof said brushes.

8. A sanding head, comprising a pair of axially spaced spiders mountableon a rotatable shaft, means adjacent the periphery of said spidersadapted for releasably locking a plurality of outwardly projectingbrushes on said spiders, a plurality of pairs of spindles carried onsaid spiders for holding a plurality of spools of abrasive strips, apinion gear on each of said pairs of spindles meshing with a sun gearnormally rotatable with the head,and means normally rotatable with thehead for rotating said sun gear with respect to the head to rotate saidspindles for unwinding the spools thereon.

9. A sanding head, comprising a pair of axially spaced spiders mountableon a rotatable shaft, means adjacent the periphery of said spidersadapted for releasably locking a plurality of outwardly projectingbrushes on said spiders, a plurality of pairs of spindles carried onsaid spiders for holding a plurality of spools of abrasive strips, apinion gear on each of said pairs of spindles meshing with a sun gearnormally rotatable with the head, and means for counter-rotating saidsun gear and head for rotating said spindles with respect to the head tounwind the spools thereon.

10. A sanding head, comprising a pair of axially spaced spidersmountable on a rotatable shaft, means interconnecting said spiders andadapted for the reception of a plurality of outwardly projectingbrushes, a plurality of pairs of spindles on said spiders for holdingspools of abrasive strips in the head, a pinion gear on each of saidpairs of spindles meshing with a sun gear, said pinion and sun gearsbeing rotatable with respect to the head to unwind said spools ofabrasive by a worm gear connected to said sun gear and driven by a wormmounted on one of said spiders, and a drum operatively connected to saidworm and movable with respect to the head for actuating said worm tounwind said spools.

l1. A sanding head, comprising a pair of axially spaced spidersmountable on a rotatable shaft, means inter connecting said spiders andadapted for the reception of a plurality of outwardly projectingbrushes, a plurality of pairs of spindles on said spiders for holdingspools of abrasive strips in the head, a pinion gear on each of saidpairs of spindles meshing with a sun gear, said pinion and sun gearsbeing rotatable with respect to the head to unwind said spools ofabrasive by a worm gear connected to said sun gear and driven yby a wormmounted on one vof said spiders, and a drum movable with respect to thehead having cammng means engaging a lever arm on said worm for drivingsaid worm to unwind said spools during movement of the drum with respectto the head.

12. A sanding head as set forth in claim 1l in which said lever arm isprovided with a ratchet for driving said worm only during movement ofthe drum with respect to the head.

13. A sanding head, comprising a pair of axially spaced spidersmountable on a rotatable shaft, means interconnecting said spiders andadapted for the reception of a plurality of outwardly projectingbrushes, a plurality of pairs of spindles on said spiders for holdingspools of abrasive strips in the head, a pinion gear on each of saidpairs of spindles meshing with a sun gear, said pinion and n sun gearsbeing rotatable with respect to the head to unwind said spools ofabrasive by a worm gear connected to said sun gear and driven -by a wormmounted on one of said spiders, a drum movable with respect to the headhaving camming means engaging a lever arm on said worm to unwind saidspools during movement of the drum with respect to the head, and stopmeans interconnecting said drum and of one of said spiders for limitingthe relative movement of the drum and the head to limit the spoolunwinding.

14. A sanding head as set forth in claim 13 in which said stop means isprovided with tension means urging said drum into normal rotationalmovement with the head.

15. A sanding head, comprising a pair rof axially spaced membersmountable on a rotatable shaft, means on each of said members adapted toreleasably lock a plurality of outwardly projecting brushes thereon, aplurality of pairs of spindles on said members for holding a pluralityof spools of abrasive strips, and a drum rotatable with respect to thehead and operatively connected to said spindles through a plurality ofintermeshing gears for 919,054 retating said spindles to unwind thespools of abrasive 1,949,565 when the drum is rotated with respect tnthe head. 2,709,323

References Cited in the flle of this patent 5 UNITED STATES PATENTS564,587 Black July 28, 1896 Milne Apr. 20, '1909 Edwards Mar. .6, 1934Swan May l31, i955 Monjar July 19, 17955

